Elevator systems are well known and in widespread use. An elevator car is supported for movement within a hoistway for carrying passengers between various levels within a building, for example. Many elevator systems include a counterweight associated with the elevator car by a roping arrangement. A machine (e.g., motor and brake) controls movement of the roping arrangement to control the movement and position of the elevator car within the hoistway.
Operating the machine requires power. It is desirable to minimize the amount of power consumed by an elevator system. One feature that has been proposed for effectively reducing the total amount of power used by the elevator system is to use the motor of the machine in a generator mode under certain conditions. For example, there are times when movement of the elevator car can be accomplished without requiring a driving force from the motor. Releasing the brake and allowing the motor to rotate responsive to movement of the associated traction sheave allows for the motor to generate electrical power. There are proposed arrangements for such use of an elevator machine.
One challenge that is presented when attempting to use an elevator machine for purposes of generating power is the introduction of additional noise. Components associated with an elevator drive that are used for purposes of generating power tend to be noisy. This issue becomes even more prominent when a machine roomless arrangement is used because the motor and drive components are contained within the hoistway. Any additional noise within the hoistway is potentially additional noise introduced into the elevator car. Maintaining a quiet and smooth elevator ride is a primary concern to elevator system designers and operators.